87 560 SL: previous owner had disconnected vacuum line from bad element in blower box. He plugged the disconnected vacuum line with a golf tee. He then cut the bad element's swing arm in half. This allowed a permanent 50-50 mix of nice cold air through the defrost and center vents. I was able to get an increase in center vent flow by placing black foam strips in the defrost vents. Problem is I don't have any air flow through the floor/lower vents in heat mode. Regardless of what i set the temperature rheostat at or which selector button I push I still get the same flow through the defrost and center vents. Seems i can only control the temperature of that flow. Now that cold weather has arrived I would like heat flow on my feet and not on my face. Is this a separate problem that can be fixed even though the defrost/center vent vacuum system has been bypassed/modified? Crossover valve unit checks out fine.